1. Field of the Invention
The present invention relates to physical disturbance monitoring systems, and more particularly, to calibration systems for such monitoring systems.
2. Description of Related Art
In a variety of hostile environments such as the inside of the containment vessel of a nuclear reactor, the need has arisen for systems to monitor the operation of apparatus in the absence of direct human supervision. Such monitoring systems typically include one or more sensors which are placed in physical proximity to the particular apparatus being monitored. Nuclear reactors often utilize a vibration and acoustic monitoring system which has a plurality of accelerometers coupled to various structures within the containment vessel of the nuclear reactor. These accelerometers can detect unusual or unexpected noises, vibrations and other physical disturbances which might be caused by malfunctioning machinery.
In order for the outputs of the sensors to be correctly interpreted, it is often necessary to periodically calibrate the sensors. Previously, monitoring system accelerometers have been calibrated using a mechanical calibration device which applies an impact force adjacent to the sensor. This operation is usually performed manually by a technician and can be a very time consuming task for monitoring systems having a large number of accelerometers. In addition, where the accelerometers are located in a hostile environment such as the radioactive interior of a containment vessel, the calibration operation can be hazardous, requiring the technicians to enter the containment vessel wearing protective radiation suits.